While postmarketing surveillance presents many of the ethical problems characteristic of research involving human subjects, this article focuses on some of the more frequently encountered issues: It is necessary to distinguish research from practice because ethical justification for these two classes of activity differs in important respects. Most research involving medical records may be conducted without informed consent provided patients are given adequate notice of such activities. Access by researchers to patients through their medical records requires careful planning to avoid what patients might consider unwelcome intrusions. Choosing the timing and format of publication of results often requires careful balancing of the interests of concerned parties such as the public, regulatory agencies, industrial sponsors and researchers.